Machines of all types generally include an assortment of gears, bearings, slides and hydraulics, and a corresponding oil based fluid system to provide for the lubrication and cooling of such parts during operation of the machine. Users of such machines have heretofore typically avoided the use of water based fluid systems because, as has long been known, a major cause of fatigue and failure in machines of this type is water, which causes hydrogen embrittlement and rapid oxidation of the metal surfaces of the gears, bearings, etc.
Machines such as automatic screw machines typically include an oil based lubrication system to provide the necessary lubrication for the gears and bearings of the device, as well as an oil based coolant system to provide a cutting coolant for the machining area of the device. Although these devices are known to perform well with a water based coolant, users have been reluctant to use water based coolants for fear that the water will leach into or otherwise penetrate the seals to the lubrication system, contaminating the oil based lubrication system with water, and promoting the failure of the gears and bearings.
However, environmental concerns have recently caused a substantial increase in the cost of disposal of oil based fluids, which must be disposed of and replaced often in many applications. Additionally, oil based fluids present an unacceptable fire hazard in certain applications such as in hydraulic systems which operate along side of welding operations. In such applications, users have been forced to utilize water based fluids, but with a substantial decrease in bearing life and corresponding increase in maintenance and replacement parts cost.
It can therefore be seen that it would be advantageous from environmental, safety and cost perspectives, to be able to convert a machine from an oil based fluid system to a water based fluid system if the conversion could be done in such a manner that the water based fluid did not cause hydrogen embrittlement, rapid oxidation, and the eventual fatigue and failure of the gears, bearings, etc. Conversion to a water based fluid system is advantageous as well in that a water based fluid dissipates heat away from gears, bearings, etc. more effectively than does an oil based fluid.
The oil used in modern internal combustion engines currently is comprised of up to about 25 to 30 percent chemical additives, including metallic and chemical friction modifiers. Since the 1920's, such additives, known as antiwear agents and extreme pressure agents have been used to supply boundary layer lubrication in the engine by creating adhering surface films through controlled surface corrosion of the metallic surfaces of the engine. The effectiveness of these chemically induced boundary layer lubrication films is limited, however, as a delicate balance must be maintained between friction reduction and increasing corrosive wear.
Furthermore, the antiwear and extreme pressure agents are typically comprised of materials now considered undesirable from an environmental standpoint. These agents may include, for example boron, sodium, magnesium, calcium, barium, phosphorus zinc, molybdenum, titanium, vanadium, and cadmium. These additives make up a substantial percentage of the total cost of the oil, and it is believed that at least a portion of these materials are emitted into the atmosphere through the exhaust system of the engine. Accordingly, it would clearly be advantageous to be able to operate an internal combustion engine with oil substantial devoid of such additives if there was no adverse effect on the wear rate.